The Nemesis Project is designed to be a commandline-based, portable human IP stack for UNIX/Linux. The suite is broken down by protocol, and should allow for useful scripting of injected packet streams from simple shell scripts.
You can download it from the following link: https://packetstormsecurity.com/files/download/10526/nemesis-v1.0pre1.tar.gz
Source: https://packetstormsecurity.com/files/10526/nemesis-v1.0pre1.tar.gz.html